In general, a touch screen is used in a mobile device, such as a mobile phone, a personal digital assistant (PDA), and a portable multimedia player (PMP), and various industrial fields, such as a navigation device, a netbook computer, a notebook computer, a digital information device (DID), a desktop computer using a touch input support operating system, an Internet protocol TV (IPTV), and high-tech fighter, tank, and armed car.
The touch screen may be added onto various types of display devices, such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode (OLED), or may be embedded inside the display device.
The OLED is an autonomous light emitting display device, in which electrons and holes injected to an organic material thin film through an anode and a cathode are re-combined to form exciton and which generates light of a specific wavelength by energy of the exciton. The OLED may be divided into an active matrix organic light emitting diode (AMOLED), a passive matrix organic light emitting diode (PMOLED), and the like.
The display device using the touch screen may be divided into a touch screen add-on type display device, a touch screen on-cell type display device, a touch screen in-cell type display device, and the like.
The touch screen add-on type display device adopts a scheme, in which a display device and a touch screen are separately manufactured, and then the touch screen is attached on an upper plate of the display device, and has a disadvantage in that a thickness thereof is large and brightness thereof is low to degrade visibility.
The touch screen on-cell type display device adopts a scheme, in which elements constituting the touch screen are directly formed on an upper substrate of a display device, for example, a surface of a color filter of an LCD or a surface of a sealed substrate of the OLED, and may have a decreased thickness than that of the touch screen add-on type display device, but still has a limit in decreasing a thickness.